Install car radio 1974

[1974targa]

Hi!
I want to reinstall my original car radio on my 1974. Unfortunately, I no longer have the installation documentation and I don't know what to do. The only thing I know is that radio requires an amplifier to be operational (I will buy one). I have 5 wires (+1 antenna) : Blue, Green, Black, Red, Red/White.

Can anybody help me please to connect it? Thanks!

https://zupimages.net/viewer.php?id=21/01/8mxc.jpg
https://zupimages.net/viewer.php?id=21/01/tkbl.jpeg
https://zupimages.net/viewer.php?id=21/01/h2rq.jpeg

[darrin]

the Lear Jet brand was a USA aftermarket brand and would not (AFAIK) have been original from the factory.

[1974targa]

You're right. Thank you. This car radio is "original" from my car - not from Porsche. Installed around 74/75.

[jjeffries]

Interesting. I just went looking on Google and found nothing (likely repeating what you’ve done). The Red is likely for 12V power; if it has a ground fitting - perhaps doubling as a mounting screw - then you **might** pair it up with a battery (and a low amp fuse ... 5A) then use an old speaker to ascertain which wires are carrying which speaker’s signals (left/right ... I didn’t see it it has front rear?).

That said, pls get another opinion or three before adding power ... I wouldn’t want you smoking this unit based on my bad advice!

An observation I might add is that this was a knock-off of Blaupunkt; specifically, I’d say it was made to resemble the CR2001/3001 range. One of those might be a nicer solution? They aren’t among the priciest of the “vintage” Blaupunkt’s one sees being sold.

Best of luck to you,
John

[76FJ55]

I see several Lear Jet 8 track manuals from that era listed on ebay. though they aren't the same model you have I would guess they would likely use similar wire color coding. you could try contacting the sellers and see if they'd be willing to send you a copy of the page for wiring.

another option would be to open the radio an look at where each wire is attached to teh circuit board, that may give a clue as to which wire has what function. Post pic's if you open it up and we'll see if we can help determine what goes where.

[bkreigsr]

Your pictures are no help.

Let's see the backside connections for power, ground, speakers and antennae.

That's all that should be involved, unless you have a motorized antennae.

[1974targa]

Hi! thanks guys for your comments. Here are the only information I have.

As I saw, this car radio need to be connected to an amplifier. Any suggestions? Thanks

[darrin]

1974targa -- suspect your radio uses a common ground for both speakers AND power, meaning the red and red/stripe wires are both power (one continuous power, the other ignition on only power, unsure which is which), and the blue and green are the positive wires for left and right speakers (again, unsure which is which). If you're OK with the possibility that this radio could be fried during the process, you could bench test the radio to a) confirm my theory and b) determine the respective roles of the two red wires and channels for the speaker wires. Common ground speaker wiring was popular/the norm many years ago, but has been replaced by floating ground speaker wiring in modern radios, where each speaker has its own positive and negative wire.